The present invention relates generally to non-volatile data storage devices, and more particularly to non-volatile data storage devices that exhibit ultra-high bit densities and very high data transfer rates. Additionally, the present invention relates to the cooperation between microelectromechanical (MEM) elements and nano-scale patterned surfaces.
Currently, there are increasing demands for non-volatile data-storage devices with higher bit density, faster speed, lower power consumption, smaller size, and lower weight than presently available state-of-the-art devices. As a result, enormous research efforts have been devoted to the study and control of key factors that will lead to the necessary technical advances. CMR (colossal magneto-resistive) and GMR (giant magneto-resistive) effects have been exploited in thin-film ferromagnetic memory technologies, such as those found in computer hard drives. Unfortunately, implementations of this memory technology require large and bulky disk-drive mechanisms with complicated moving parts.
Proximal-probe techniques such as AFM (atomic force microscopy), MFM (magnetic force microscopy), SPM (scanning probe microscopy), thermomechanical writing, and many others have also been proposed for ultra-high density memory devices, but few of these efforts have yielded practical implementations.
Chip-based non-volatile devices such as ferroelectric memories, EPROMs (eraseable programmable read-only memories), and EEPROMs (electronically erasable programmable read-only memories) generally suffer from high manufacturing costs. Most critically, bit densities are severely limited by the size of the transistors used to write and read the digital information stored in each memory cell. However, chip-based memories enjoy the advantages of a complete write and read system contained in a single device with no moving parts.
Accordingly, there exists a distinct need for a non-volatile memory device that can combine the integral read/write capabilities and small size of chip-based memories with the ultra-high bit density capabilities of proximal-probe techniques.
In accordance with the present invention, a micron-scale, self-contained, ultra-high density and ultra-high speed storage device that is both re-writeable and non-volatile comprises two primary complementary components: a read/write head and a surface, containing bit-storage domains, that acts as the storage medium. The read/write element of the memory device may include a single or multiple heads mounted, for example, on microelectromechanic structures (MEMS) driven at mechanical resonance. Addressing of individual bits is accomplished by positioning the head element in close proximity to bit domains situated on the storage medium.
In one embodiment, individual bit domains are formed by nanoprinting. In a second embodiment, bit domains are formed by self-assembling metal-organic structures. In a third embodiment, a continuous electronically writeable film is created.
X-Y translation of a read/write head may be accomplished by vibrating motion in cross-mounted MEM structures. Alternatively, the read/write head may be fixed to a stationary support, with the memory medium attached to a MEM translation structure.
In another aspect of the invention, storage devices in accordance herewith are employed as universal Turing machines.